Prime Minister Shinzo Abe's recent push to engineer Japan's first revision to the pacifist Constitution continued to cause ripples in the political community on Thursday, with even senior members of his ruling Liberal Democratic Party raising questions.

"I don't think the Constitution can be revised when only poor discussions are taking place. No way should a constitutional amendment be driven by impulse," former Defense Minister Shigeru Ishiba, who is seen as a potential successor to Abe as LDP leader, said at a meeting of a group of lawmakers he leads.

Foreign Minister Fumio Kishida said at a separate gathering that his opinion has not changed since 2015, when he said he was against an immediate revision to war-renouncing Article 9, though Abe proposed amending the sensitive article at a gathering to mark the 70th anniversary of the Constitution taking force on May 3.